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        window.onload = function () {
            function fnAdd(a, b) {
                var c = a + b;
                alert("内部的C = "+c);
                //alert(c);
                return c;  //可以结束函数的运行 
            }

            var iResult = fnAdd(2, 5);
            alert(iResult);


        }
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    <title>Document</title>
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